Mapping the Efficiency of a Double Acting, Single-Rod Hydraulic-Actuator Using a Critically Centered Four-Way Spool Valve and a Load-Sensing Pump

In this paper, an efficiency map is created for a double-acting, single-rod hydraulic-actuator using a critically centered four-way spool valve and a load-sensing pump. The purpose of this research is to provide an understanding of the performance of a valve-controlled hydraulic actuator under all operating conditions. This paper considers a four-quadrant set of operating conditions, where each quadrant represents a different combination of actuator retraction or extension and overrunning or resistive loading. This four-quadrant efficiency map is the first presentation of its kind in the literature, and clearly demonstrates the performance characteristics and limitations for this hydraulic system. For its most common operation of an actuator extending under a resistive load, the map shows that this system can operate at over 82% efficiency and can move large loads. The map also shows physical limitations for the system, such as maximum pressure limits, maximum displacement limits, and valve limits. The efficiency map is plotted in nondimensional form, which presents the most general understanding of system performance and also allows dimensional values to be reconstructed for a similar system of any size.